I have to say that I doesn’t always play with 3 colors all the time, only mostly on 4* tournament. Overall, it is depend on how strong your heroes and troops are compare to the enemy team.
In war and 5* tournament, I usually play with 4-1 that my heroes and troops aren’t as strong as those whale defense. And yes, I doesn’t end well like my 3* and 4* result tournament.
I am like 95% to get kick out of 5* tournament in day 4 and end with top 10% loot. (However, this might be change after I get Kara and Milena up to 85+20 ).
On war I still go with 4-1 as well since I have to spread my strong heroes and I attack the stronger team since I am one of the best war attacker in my alliance.
For 3* tournament, it is depend but I most go with 3-2 since most people have strong 3* defense. I might go with 3 color if I face weak or moderate defense team.
For the 4* tournament, I usually go with 3 color since my heroes and troops are as strong as the enemy team.
However, you have to go with the right heroes.
In buff booster, I usually go with 3-1-1 or 2-2-1 with 3 healers of each different color but sometimes go with only 2 healers depend on enemy team and the color that can be used.
In bloody battle, I usually go with 3-1-1 or 2-2-1. The 1 stack is minion summoner or C Kelile. However, I might go with 3-2 if I can’t find the 1 stack that is minion summoner or C Kelile that I can use because 1 stack of hero that isn’t minion summoner or C Kelile doesn’t make much different. Also depend on enemy team as well. For example, 1 green stack of CB Caedmon is ok against Ferant tank.
In rush attack, I go with Little John + Mielikki + C Caedmon/C Melendor + Zhabog + Healer for now. Not sure if it is still work well or not after the S1 family update that my C Caedmon/C Melendor can’t charge in 6 tile any more.
Overall, it depend on how strong your heroes and troops are compare to the enemy team, how well your heroes to counter their team and do you have the right hero that can make a significant change in the battle even the hero is only on 1 stack .